Thursday, October 2, 2008
Wednesday, October 1, 2008
Ok, I'm shocked this is news
Of course this is the obvious thing to do when solar panels are more common and to make them even more common.
Sunday, September 28, 2008
From the Science Daily--solar topics
Absorbing more of the spectrum
Using OLED technology for solar power.
“We’re working on synthesizing novel polymers with variable band gaps, including high, medium and low-band gap varieties, to absorb the full spectrum of sunlight. By this we can double the light harvesting or absorption,” Qiao said.
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Roads as water heaters/solar energy creators:
“Asphalt has a lot of advantages as a solar collector,” Mallick says. “For one, blacktop stays hot and could continue to generate energy after the sun goes down, unlike traditional solar-electric cells. In addition, there is already a massive acreage of installed roads and parking lots that could be retrofitted for energy generation, so there is no need to find additional land for solar farms. Roads and lots are typically resurfaced every 10 to 12 years and the retrofit could be built into that cycle. Extracting heat from asphalt could cool it, reducing the urban ‘heat island’ effect. Finally, unlike roof-top solar arrays, which some find unattractive, the solar collectors in roads and parking lots would be invisible.”
Hot water flowing from an asphalt energy system could be used “as is” for heating buildings or in industrial processes, or could be passed through a thermoelectric generator to produce electricity.
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Slicing Wafer better lowers costs of solar cells.
"We're coming up with a more efficient way of making germanium wafers for solar cells – to reduce the cost and weight of these solar cells and make them defect-free."
The new method for slicing solar cell wafers – known as wire electrical discharge machining (WEDM) – wastes less germanium and produces more wafers by cutting even thinner wafers with less waste and cracking. The method uses an extremely thin molybdenum wire with an electrical current running through it. It has been used previously for machining metals during tool-making.
Germanium serves as the bottom layer of the most efficient existing type of solar cell, but is used primarily on NASA, military and commercial satellites because of the high expense – raw germanium costs about $680 per pound. Four-inch-wide wafers used in solar cells cost $80 to $100 each, and the new cutting method may reduce the cost by more than 10 percent, . . .
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Old news here
Thin films solar cells
Silicon is the material of choice in the electronics industry because of its stability, non-toxicity and ubiquity. However, silicon is a poor absorber of light. In a bid to drive down costs, scientists have moved from using expensive thick silicon “wafers” to cheaper “thin film” cells, containing less silicon.
********************************************************
Using OLED technology for solar power.
“We’re working on synthesizing novel polymers with variable band gaps, including high, medium and low-band gap varieties, to absorb the full spectrum of sunlight. By this we can double the light harvesting or absorption,” Qiao said.
**********************************************
Roads as water heaters/solar energy creators:
“Asphalt has a lot of advantages as a solar collector,” Mallick says. “For one, blacktop stays hot and could continue to generate energy after the sun goes down, unlike traditional solar-electric cells. In addition, there is already a massive acreage of installed roads and parking lots that could be retrofitted for energy generation, so there is no need to find additional land for solar farms. Roads and lots are typically resurfaced every 10 to 12 years and the retrofit could be built into that cycle. Extracting heat from asphalt could cool it, reducing the urban ‘heat island’ effect. Finally, unlike roof-top solar arrays, which some find unattractive, the solar collectors in roads and parking lots would be invisible.”
Hot water flowing from an asphalt energy system could be used “as is” for heating buildings or in industrial processes, or could be passed through a thermoelectric generator to produce electricity.
********************************************************
Slicing Wafer better lowers costs of solar cells.
"We're coming up with a more efficient way of making germanium wafers for solar cells – to reduce the cost and weight of these solar cells and make them defect-free."
The new method for slicing solar cell wafers – known as wire electrical discharge machining (WEDM) – wastes less germanium and produces more wafers by cutting even thinner wafers with less waste and cracking. The method uses an extremely thin molybdenum wire with an electrical current running through it. It has been used previously for machining metals during tool-making.
Germanium serves as the bottom layer of the most efficient existing type of solar cell, but is used primarily on NASA, military and commercial satellites because of the high expense – raw germanium costs about $680 per pound. Four-inch-wide wafers used in solar cells cost $80 to $100 each, and the new cutting method may reduce the cost by more than 10 percent, . . .
********************************************************
Old news here
Thin films solar cells
Silicon is the material of choice in the electronics industry because of its stability, non-toxicity and ubiquity. However, silicon is a poor absorber of light. In a bid to drive down costs, scientists have moved from using expensive thick silicon “wafers” to cheaper “thin film” cells, containing less silicon.
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Sunspots haven't returned, now this
Don't know what is up with the Sun these days. First our sun spots are still missing. Not that their absence is outside of statistical norms but it is getting close. And then the solar wind is acting wonky.
AR coating review--techonology overview
Specific patents listed below.
Patent Review: AR coatings: doing more than reflecting less
David Waechter, Nerac analyst
The quest for higher efficiency in solar cells and LED lighting, and reducing glare from display screens, have led to a dramatic increase in antireflective coating patents.
David Waechter, Nerac analystThe concept of using a coating to reduce surface reflection has been known for many years. Yet the technology continues to advance, and patent activity shows no sign of slowing down. An additional focus is films that do more than just reduce reflection.Lord J.S. Rayleigh demonstrated in 1879 that a graded index-of-refraction layer could reduce reflection over a broad range of wavelengths (On the reflection of vibrations at the confines of two media between which the transition is gradual, Proc. London Math. Soc., 11 (1879) pp. 51-56). However in Rayleigh's day, there were relatively few applications for this effect.
In the modern world there is a strong impetus to push the technology to its limits because of the need for higher efficiency in solar cells and LED lighting, as well as the need to reduce glare from display screens. Patents in this technology continue to grow especially in countries other than the United States. The number of U.S. patent titles that refer to antireflection coatings in the first 7-1/2 years of this century is almost twice that of the 1990s. Even larger increases have occurred for European patents. And the Japanese patent office has been publishing significantly more patent applications in this area than the United States and Europe combined.
In practical implementations, it is common to use a single layer of constant index to reduce the reflectivity to zero at a chosen wavelength at normal incidence. Multi-layers or graded layers can provide low reflectance over a broader bandwidth, but usually with greater cost. In the case of single layers on silicon solar cells, for example, the chosen wavelength is optimized to maximize efficiency, while taking into account the solar spectrum, the silicon band gap and electrical loss mechanisms. The optimum coating thickness gives silicon cells the deep blue color that can be seen on solar farms and rooftops in ever-increasing numbers. Yet we know that if the coating stopped all reflection, the cells would appear jet black from any angle. Achieving this in a cost-effective manner has been elusive, but progress continues.
While a great deal of attention has rightly been placed on improving the reflectance properties, simultaneously achieving other technical benefits has been receiving attention too. Examples include improving physical hardness and abrasion resistance, as well as providing electrical conduction and even providing defogging properties. And lower cost processes will always attract attention. What else is being patented today? Here are some examples from filings with the U.S. Patent and Trademark Office:
US07374812: Low refractive index coating composition for use in antireflection polymer film coatings and manufacturing method.This patent by 3M describes a silicone-modified fluoropolymer that is suitable for displays. It uses higher fluorine content to achieve lower refractive index while also improving adhesion.
US07332213: Hardcoat film, antireflection film and equipment for display.This patent by Torray Industries describes a hard-coat anti-reflecting film for displays that has a mean reflectance between 400 and 600 nm of 1 percent or less.
US07153584: Hybrid film, antireflection film comprising it, optical product, and method for restoring the defogging property of hybrid film.This patent by Hoya Corporation describes films for lenses that provide both defogging and antireflection properties.
US07283303: Conductive anti-reflection coating.This patent by JDS Uniphase breaks up a quarter wave layer into smaller portions using thin layers of conductive material to provide a solid electrical contact with low contact resistance.
US20060099407: Antireflective coating composition, antireflection film, and fabrication method thereof.This application describes an anti-reflection coating with better mechanical strength. It achieves low index of refraction by using cross-linked colloidal particles with distributed nanopores.
US20060074172: Antiglare and antireflection coatings of surface active nanoparticles.This application from Optimax Technology Corporation describes a process for preparing durable antireflection coatings that use low and high refractive index layers with a self-assembling gradient layer in between.
Patent Review: AR coatings: doing more than reflecting less
David Waechter, Nerac analyst
The quest for higher efficiency in solar cells and LED lighting, and reducing glare from display screens, have led to a dramatic increase in antireflective coating patents.
David Waechter, Nerac analystThe concept of using a coating to reduce surface reflection has been known for many years. Yet the technology continues to advance, and patent activity shows no sign of slowing down. An additional focus is films that do more than just reduce reflection.Lord J.S. Rayleigh demonstrated in 1879 that a graded index-of-refraction layer could reduce reflection over a broad range of wavelengths (On the reflection of vibrations at the confines of two media between which the transition is gradual, Proc. London Math. Soc., 11 (1879) pp. 51-56). However in Rayleigh's day, there were relatively few applications for this effect.
In the modern world there is a strong impetus to push the technology to its limits because of the need for higher efficiency in solar cells and LED lighting, as well as the need to reduce glare from display screens. Patents in this technology continue to grow especially in countries other than the United States. The number of U.S. patent titles that refer to antireflection coatings in the first 7-1/2 years of this century is almost twice that of the 1990s. Even larger increases have occurred for European patents. And the Japanese patent office has been publishing significantly more patent applications in this area than the United States and Europe combined.
In practical implementations, it is common to use a single layer of constant index to reduce the reflectivity to zero at a chosen wavelength at normal incidence. Multi-layers or graded layers can provide low reflectance over a broader bandwidth, but usually with greater cost. In the case of single layers on silicon solar cells, for example, the chosen wavelength is optimized to maximize efficiency, while taking into account the solar spectrum, the silicon band gap and electrical loss mechanisms. The optimum coating thickness gives silicon cells the deep blue color that can be seen on solar farms and rooftops in ever-increasing numbers. Yet we know that if the coating stopped all reflection, the cells would appear jet black from any angle. Achieving this in a cost-effective manner has been elusive, but progress continues.
While a great deal of attention has rightly been placed on improving the reflectance properties, simultaneously achieving other technical benefits has been receiving attention too. Examples include improving physical hardness and abrasion resistance, as well as providing electrical conduction and even providing defogging properties. And lower cost processes will always attract attention. What else is being patented today? Here are some examples from filings with the U.S. Patent and Trademark Office:
US07374812: Low refractive index coating composition for use in antireflection polymer film coatings and manufacturing method.This patent by 3M describes a silicone-modified fluoropolymer that is suitable for displays. It uses higher fluorine content to achieve lower refractive index while also improving adhesion.
US07332213: Hardcoat film, antireflection film and equipment for display.This patent by Torray Industries describes a hard-coat anti-reflecting film for displays that has a mean reflectance between 400 and 600 nm of 1 percent or less.
US07153584: Hybrid film, antireflection film comprising it, optical product, and method for restoring the defogging property of hybrid film.This patent by Hoya Corporation describes films for lenses that provide both defogging and antireflection properties.
US07283303: Conductive anti-reflection coating.This patent by JDS Uniphase breaks up a quarter wave layer into smaller portions using thin layers of conductive material to provide a solid electrical contact with low contact resistance.
US20060099407: Antireflective coating composition, antireflection film, and fabrication method thereof.This application describes an anti-reflection coating with better mechanical strength. It achieves low index of refraction by using cross-linked colloidal particles with distributed nanopores.
US20060074172: Antiglare and antireflection coatings of surface active nanoparticles.This application from Optimax Technology Corporation describes a process for preparing durable antireflection coatings that use low and high refractive index layers with a self-assembling gradient layer in between.
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